Ultrasonic welding of micro plastic parts

W. Michaeli (a), E. Haberstroh (b), W.-M. Hoffmann (a)

(a) Institute of Plastics Processing (IKV), RWTH Aachen University, Aachen, Germany
(b) Lectureship and Research Field of Rubber Technology, RWTH Aachen University, Germany

Abstract

Due to the ongoing miniaturisation in many industrial branches plastics are increasingly applied in microsystems technology. To guarantee the functionality of the system suitable joining processes must be applied to join separate components. Most of the welding processes commonly used for series production are not suitable for welding micro parts made from plastics, since either the mechanical or the thermal load of the joining partners during the welding process are too high. Only laser transmission welding and ultrasonic welding are applicable for welding complex micro components. Since with ultrasonic welding a certain frictional load of the components cannot be avoided totally with standard welding equipment, specially adapted machinery has to be used as it could be shown at the Institute of Plastics Processing (IKV) at RWTH Aachen University. While micro parts with two-dimensional weld seams have already been successfully welded in previous investigations, recent research deals with the ultrasonic welding of micro parts with a more complex three-dimensional weld seam geometry. It could be shown that for appropiate welding parameters this can be accomplished, whereby the mechanical load of the parts has to be kept as small as possible.